Process For The Treatment And The Winemaking Of Grapes

ABSTRACT

A grape treatment and wine making process characterised by the steps of: cleaning a first container by means of a fluid mixed with ozone; placing the grapes in said first container in closed vats and/or buildings at controlled temperature; diffusing a fluid mixed with ozone within said vats and/or buildings at controlled temperature; cleaning said grapes placed in said first container by means of a fluid mixed with ozone; cleaning a press by means of a fluid mixed with ozone; pressing said grapes with said press to produce must; cleaning a second container by means of a fluid mixed with ozone; placing said must in said second container to produce fermented must; cleaning a third container by means of a fluid mixed with ozone; placing said fermented must (wine) in said third container.

The present invention relates to a grape wine making process, inparticular a wine making process using ozone, and to the wine obtainedin this manner.

In the agrofood and wine making industry, disinfection is an extremelyimportant procedure. For this purpose chlorine or other chemicalcompounds are generally used such as, in the case of grapes and wine,sulphur dioxide, which in addition to eliminating the overall microbialload present in the product, can also to cause quality alterations andallergic effects in some consumers.

Sulphitation is also a frequent practice in the biological field as itperforms the function of oxidation control and microbial developmentcontrol, and enables must acidification. These important advantages areaccompanied by a large number of significant disadvantages: hydrogensulphide formation and hence bad odour; wine ripening delay due tomalolactic fermentation; toxicity in man (mutagenic and allergic effect)in the form of bronchospasms, irritations etc. Another notinconsiderable problem is that the sulphite ion easily binds to sugarsand to ketonic acids in which the grape must and then the wine are rich,so that the sanitizing effect decreases. Moreover the sulphites arealways added in excess to ensure that a free sulphurous and hencesanitizing quantity is available. If from a wine making viewpoint thefree availability is the more important, for the consumer it is thetotal quantity (combined+free) which counts, this generally being up to5 times more, depending on the wine.

The first sulphite addition takes place immediately on arrival of thegrapes in the hopper or with the arrival of the pressed product, to aquantity of about 10 g per 100 kg of grapes.

At the end of alcohol fermentation the total sulphite and free SO₂levels are checked to verify that these are at least 40 mg/l of totalsulphites and 14 mg/l of free SO₂: if the level is less, furthersulphites are added to reach the required level by adding potassiummetabisulphite, knowing that 1 g of metabisulphite per 100 litresproduces about 2 mg of free SO₂ and about 5 mg of total sulphites perlitre.

At the end of malolactic fermentation, sulphite is again added to bringthe total sulphite concentration to 30 mg/l and the free SO₂concentration to 22 mg/l.

The concentrations are even higher for white wines and even more forsweet wines.

The stated levels are those used in Italy, whereas in countries such asGermany and Austria the total sulphite levels can even reach 120 mg/lbecause of the greater susceptibility to acetic grape fermentation dueto field inoculation in relation to climatic conditions, and because ofa higher residual sugar quantity than that of so-called dry wines.

The document CN101438733 describes the sterilization of red table grapesby washing them for 10-15 minutes with water mixed with ozone (10-12 ppmof ozone). Hence an alternative sterilization is described for a productfor immediate consumption having organoleptic characteristics differentfrom wine-making grapes. No suggestion is given as to how such a processcan also be used for a lengthy complex procedure such as grape winemaking.

The Applicant has studied and considered experimental results obtainedby treating harvested products, in terms of elicitation effect due toinduced superoxidative stress, by the stimulus and accumulation of addedvalue substances of salutistic type for man (mainly flavanol, flavonolsand stilbenes).

The Applicant has also realized that a further positive characteristicof ozone is represented by the high instability of the molecule used inthe form of ozone (O3), which rapidly degrades to reform oxygen (O2)without leaving residues which are harmful or which can negatively alterthe wine quality. This characteristic is considered positive within theframework of also using ozone sterilization in a long-duration processsuch as wine making and in wine-making processes of biological type.

The Applicant has further realized that if the grapes and all thematerials used in wine production were treated with ozone it would nolonger be necessary to add sulphites to prevent wine contamination.

An object of the present invention is to provide a process for grapetreatment and wine making which enables the grapes to be sanitized andtheir microbial load to be eliminated such as to enable a considerablereduction in the use of sulphitation.

Another object is to provide a process which produces a stress effect ofinduced oxidative nature on the grapes, such as to act as a stimulus forthe synthesis/accumulation of substances (secondary metabolites)recoverable in the grapes and in the final product (wine), andconsidered as of nutritious power for the health of the consumer andhaving a quality value for the wine.

A further object is to provide a process which produces a stabilizationeffect on the final product (wine), enabling the addition of sulphitesto be avoided on termination of the wine making process.

Finally, another important object is to reduce the environmental impactof the process in view of the low energy consumption in producing ozone,the reduction in water consumption and its recycling, the lesser CO₂emission compared with the production of sulphites and detergentssynthesized industrially, and the complete absence of residualcontaminants.

According to the present invention, these and further objects areattained by a grape treatment and wine making process characterised bythe steps of: cleaning a first container by means of a fluid mixed withozone; placing the grapes in said first container in closed vats and/orbuildings at controlled temperature; diffusing a fluid mixed with ozonewithin said vats and/or buildings at controlled temperature; cleaningsaid grapes placed in said first container by means of a fluid mixedwith ozone; cleaning a press by means of a fluid mixed with ozone;pressing said grapes with said press to produce must; cleaning a secondcontainer by means of a fluid mixed with ozone; placing said must insaid second container to produce fermented must; cleaning a thirdcontainer by means of a fluid mixed with ozone; placing said fermentedmust in said third container.

Further characteristics of the invention are described in the dependentclaims.

The advantages of this solution compared with the solutions of the artare various.

Those grapes which have undergone treatment in accordance with thepresent invention presented the advantage of eliminating the microbialload originally present on the berry surface to a level such as not onlynot to prejudice the quality and health of the wine, but indeed toimprove its health by eliminating pathogenic fungi able to produceochratoxins. The treatment also results in reduction in indigenous yeastlevels normally located on the grape skin. This means that thesulphitation procedures used in traditional wine making processes tocontrol the triggering of spontaneous formation can be avoided.

A further surprisingly innovative advantage obtained by the describedprocess is given by the stimulation and/or accumulation of value addedsubstances advantageous for the properties of the grapes and of the wineproduced by them together with facilitating their extraction from thegrapes, in particular polyphenols the most important of which areflavonols, flavanols, stilbenes and phenolic acids (gallic acid). It hasin effect been found that the grapes react to the stress of the ozonetreatment by increasing the concentration of these substances, and thatthese substances are transferred by the grapes (berries) to the winewith greater ease, so increasing their concentration.

In particular, a high and significantly higher polyphenol andanthocyanin extraction in red wines (between 35 and 50%) is obtained dueto a combination of mechanisms: exposing the grapes to ozone at thecorrect concentration and for the correct times stimulates theproduction of these compounds in the grapes before pressing, anddetermines skin permeability, resulting in greater extractability.Treatment at the correct concentration for the correct duration alsofavours synthesis and extractability of aromatic compounds. Theantiseptic effect of ozone makes it possible not to add sulphites duringwine making because bacteria, yeasts and mould are eliminated on thestarting grapes, and all the equipment used is sterilized.

Paradoxically, a wine can be produced without sulphites which is treatedwith ozone to achieve greater polyphenol and anthocyanin extraction,then adding sulphites before bottling to ensure its long term stability,the product obtained being in any event different from that produced byadding sulphites onto the grapes before pressing. The pre-harvestingresidues present on the grapes (pesticides, herbicides, etc.) areeliminated as the ozone oxidizes them. Pesticides and herbicides aresubstances sensitive to oxidation and treatment with ozone, which is asuper-oxidant and neutralizes their active principle.

Again, there is the advantage of favouring stabilization of the wineproduced from ozonized grapes by reducing the sulphite levels to onlythe residues originating from the fermentation yeasts.

In addition the water used for washing can be discharged withoutproblems as it is not contaminated chemically but possibly onlybiologically, and if this latter is the case it can be treated withozone to hence make it reusable for irrigation or for some otherprofitable use.

The characteristics and advantages of the present invention will beapparent from the ensuing detailed description of one embodimentthereof, given by way of non-limiting example.

The process provides for wine making in a suitable room previouslywashed with ozonized water and/or fumigated with ozone in gaseous form,using equipment disinfected by treatment with ozone in air and/or inwater. This is also the case if wooden containers are used, whichalthough having the advantage of a certain permeability and the transferof pleasant flavours, have the problem of easy contamination, forexample by Brettanomyces, which is difficult to resolve with normalwater treatment.

Washing with ozonized water and/or fumigation with gaseous ozone havethe additional object of annulling the drawbacks associated with the useof wooden casks.

The process comprises the production of ozonized water by a specificgenerator provided with a computerized system, able to continuously blowozone into the aqueous medium and to ensure the control andstabilization of all the required parameters (ozone concentration, watertemperature, ozonized water volume).

The purpose of washing the grapes in ozonized water is to ensure aninitial removal or decrease of microflora, with particular attention toBotrytis cinerea and other pathogenic fungi which can produceochratoxin, but also to bacteria which can alter the wine (acetic andlactic bacteria). In this respect, normal wash procedures have shown aninsignificant reduction in Botrytis cinerea compared with grapes storedwithout any water intervention.

The process also makes it possible to disinfect the rooms andinstruments used for wine making by blowing in ozone in gaseous form.Again in this case the operation is controlled and entirely managed by aspecific ozone generator provided with a computerized system able tomaintain a constant ozone concentration and blowing time controlled atthe values necessary to achieve the object.

The grapes, even if not subjected to the wash process, are located inone or more layers in perforated plastic boxes of the type used forwilting/dehydration procedures within confined environments, such ashermetically sealed buildings. The boxes can have dimensions andconsequent product loading capacities which are variable (from 3-5 to8-10 kg) and can be handled on pallets. This characteristic enablespiles of boxes to be organized containing grapes in a form such as to beable to utilize in the most suitable manner the internal spaces of thededicated rooms and the effective movement of the internal air with thepurpose of making the gaseous ozone treatment uniform and efficient.This treatment takes place by the controlled infeed of the ozoneproduced by the generator, which is able to ensure continuous control ofquantities (concentrations) and grape exposure times within theaforesaid controlled rooms, in which the relative temperature andhumidity conditions for the grapes are suitably monitored andcontrolled.

Suitably arranged ventilation systems are provided for correct movementof the internal air and to favour effective diffusion of the gaseousozone which strikes the grape bunches and hence the grape berries byalso passing through the perforated structure of the boxes. Effectivereaching of the entire surface of the grape berries is also facilitatedby preferably locating the grape bunches in a single layer on the boxfloor. The rooms used for storage and for the treatment operations arepreviously adequately sanitized by washing with ozonized water and/or byinfeeding gas at higher concentrations than those scheduled for theproduct treatments.

The ozone necessary for the process is produced in known manner, forexample by the corona discharge method which enables air to be obtainedwith ozone concentrations up to about 6% by weight.

An ozone production unit using the corona effect consists of thefollowing parts: an oxygen source, anti-dust filters, gas driers, ozonegenerators, contact and catalytic destruction unit. For ozoneproduction, atmospheric air (provided by a compressor) or air enrichedwith pure oxygen can be used.

The quantity of ozone-containing air depends on the grape quantity. Forexample for 2.8 metric tons of grapes, stored in boxes containing grapesin a single layer and located in a closed building, a sterilizationprocess was carried out lasting 12 hours. In the first 4 hours 40 g/hourof ozone were blown in, with 1 g/hour of ozone blown in during the next8 hours, for a total of 168 g of ozone, equivalent to about 60 g foreach metric ton of grapes.

In the building, at the exit for the blown air, a manganese dioxideconverter is located to convert the remaining ozone into oxygen.

The treatment duration can be chosen according to the particular case.For example, if the ozone production is low, the duration can be longer.In any event, the concentration must be initially very high to quicklysaturate the building and to accelerate initial sterilization of eventhe minimum product contamination. When the environment is saturated,the procedure switches to maintaining the ozone quantity present in thebuilding.

For washing with water containing ozone, the water is prepared byenriching it with ozone to reach a concentration of 6-8 mg of ozone perlitre of water at 15° C.

Contact with the grapes (and with the equipment used in the process)takes place by immersion or by spraying.

In particular, by washing the grapes with water containing ozone, thewater droplets remain partially on the grape berries to prolong the timeof the sterilization process.

To wash the equipment used in the process, a wash of about one hour iscarried out with an ozone concentration of about 6-8 mg per litre ofwater.

According to the proposed procedure, after sanitizing with ozone inwater and/or in air, the grapes are poured into the stalk stripperpreviously washed with ozonized water and/or fumigated with gaseousozone, its exit pipe leading directly to the press, also previouslywashed with ozonized water and/or fumigated with gaseous ozone.

After completing pressing, the must is collected in a hopper or vesselcleaned with ozonized water and/or fumigated with gaseous ozone, andcollected in containers previously treated with ozonized water and/orozone in the gaseous phase.

When the container is filled, fermentation proceeds. The upper hole ofthe container through which the must has been introduced is closed witha suitable stopper washed with ozonized water and/or fumigated withgaseous ozone, without the need for previous addition of potassiummetabisulphite (antimicrobial antioxidant preservative).

On termination of all the wine making steps, the wine produced is pouredinto containers (bottles) previously washed with ozonized water and/orfumigated with gaseous ozone.

The ozone treatment conducted on the grapes has provided importantresults with regard to the phenolic fraction as can be seen in Table 1.In this respect, after just one day of treatment, while the anthocyaninfraction has not undergone variation, other phenolic fractions such asgallic acid, catechins and epicatechins have demonstrated significantlyhigh increments as can be seen from Table 2. This signifies a strongactivation of the antioxidant phenolic fractions which play an importantrole from the enological (stabilization) and health viewpoint.

Table 3 below show the values of chemical analyses of enologicalinterest conducted on 33 different wine batches, of which No. 15corresponds to the batch in which ozone was used on the grapes and forwashing the wine making equipment, and in which sulphites were not usedin the wine making. It can be seen that the wine, originating fromwilted grapes and treated with ozone for one week, has about 15° alcoholwith a residual sugar level of 1.30 g/l, the lowest value of allsamples, indicating that fermentation has taken place very regularly.This could be attributed to the greater ease with which the yeasts haveacted, not finding competitors. The volatile acidity, which in theabsence of sulphur dioxide represents an index of the risk of irregularfermentation, has instead remained in line with the other wines (0.28g/l). The total and free SO₂ have remained very low and significantlylower than in the other wines. It is no surprise to also find SO₂ valuesin non-sulphurated wines. This is because yeasts themselves areproducers of sulphurated compounds, and more so under stress conditions.Hence the level found can be considered physiological. An interestingconfirmation of the aforestated is the significant increase in tanninswhich is the second highest of all the batches.

The development of the wine over time while in the steel container wasregular without any sulphur dioxide increase during the malolacticfermentation which as can be seen from the final malic acid value (0.05)proceeded regularly. The volatile acidity underwent a slightphysiological increase with the malolactic fermentation but alwayswithin the limits of a good quality wine.

Finally the polyphenolic fraction (anthocyanins, total polyphenols,tannins) remained unaltered during the progress of the malolacticfermentation.

The increase in polyphenols and anthocyanins can be noted from Table 4,which relates to bottled wines of two years ageing with the grapes andall the used equipment cleaned with ozone in accordance with theaforestated quantities. Hence a wine can be noted containing polyphenolsand anthocyanins in a greater percentage than that of a wine produced bythe traditional process, and in particular polyphenols 30% greater andanthocyanins 60% greater.

TABLE 1 Peonidin 3 Malvidin 3 Peonidin 3 Malvidin 3 Delfidin 3 Cyanidin3 Petunidin 3 Peonidin 3 Acetyl Malvidin 3 Acetyl Cumaroyl CumaroylSample Glucoside Glucoside Glucoside Glucoside Glucoside GlucosideGlucoside Glucoside Glucoside Total 09- 3 0.6 3.2 5.5 2.0 45.7 33.1 0.76.2 42.0 september 10- 2 0.4 2.6 6.4 2.2 47.7 31.8 0.8 6.1 40.9september

TABLE 2 PFT Index 280 Gallic Anthocyanins Anthocyanins (pH acidCatechins Epicatechins Sample pH 1 pH 3.2 Extract % 1) ppm ppm ppm 09-65 33 49 14.2 21 2 18 september 10- 65 32 51 15.3 29 3 30 september

TABLE 3 Net Malic Total Sugars Total Volatile Total Free Colour AcidPolyphenolsi

Anthocyanins Tannins N^(o) Alcohol (g/l) Acidity pH Acidity SO2 SO2Intesity Tonality (g/L) (mg/l) (mg/L) (g/L) 1 12.71 2.75 6.15 3.13 0.2950 20 36.380 0.331 1.93 3918 791 3.95 2 14.38 2.15 5.73 3.55 0.38 77 2310.540 0.528 1.39 2670 358 3.31 3 13.77 2.35 5.61 3.57 0.36 69 22 7.2300.578 1.46 2374 312 3.05 4 13.26 2.25 5.58 3.58 0.34 72 19 7.000 0.6071.09 2824 282 2.28 5 13.83 2.20 5.51 3.59 0.27 62 22 6.890 0.612 1.32595 299 2.95 6 13.35 2.10 7.1 3.39 0.21 50 18 7.730 0.592 1.8 3341 5153.84 7 11.79 1.75 6 3.39 0.28 36 11 4.740 0.535 1.66 1679 123 2.42 814.97 2.90 8.08 3.07 0.33 45 13 8.780 0.456 1.29 2211 94 3.41 9 13.842.40 6.63 3.25 0.29 32 10 7.440 0.514 1.19 1870 81 3.11 10 12.30 2.706.5 3.34 0.28 35 11 6.620 0.513 1.38 1819 89 2.31 11 12.46 2.30 6.5 3.30.27 39 13 5.160 0.497 1.47 1598 72 2.09 12 12.82 2.55 6.39 3.34 0.36 3712 5.550 0.513 1.39 1601 60 2.87 13 13.37 2.56 6.24 3.3 0.27 40 13 6.8600.548 1.25 1924 73 2.89 14 13.59 2.61 6.54 3.23 0.30 34 12 6.640 0.5201.26 1722 75 2.47 15 14.81 1.30 6.88 3.44 0.28 25 7 10.340 0.532 2.252547 180 3.89 16 12.78 1.70 6.76 3.36 0.33 41 14 13.920 0.413 1.46 2511338 3.02 17 12.69 2.40 7.88 3.17 0.39 31 11 15.930 0.392 1.12 2421 2273.07 18 14.53 2.30 5.31 3.55 0.47 36 12 13.250 0.554 1.2 2884 308 3.8319 14.93 2.50 5.96 3.43 0.42 33 10 10.210 0.630 1.91 2116 199 3.37 2012.88 2.00 5.54 3.56 0.23 56 19 13.290 0.448 1.46 2647 292 3.53 21 14.604.20 6.92 3.34 0.43 61 18 13.270 0.520 1.56 2450 280 3.34 22 14.81 2.907.55 3.24 0.39 45 14 15.790 0.456 1.55 2698 295 3.78 23 15.31 2.40 7.873.14 0.35 33 12 19.340 0.426 1.65 2703 340 3.65 24 14.73 3.20 8.25 3.10.38 53 16 9.240 0.451 1.32 2235 190 3.2 25 14.39 2.50 5.33 3.66 0.40 7524 8.980 0.660 1.34 2573 195 3.45 26 14.71 10.90 7.77 3.22 0.52 63 1410.890 0.552 1.59 1443 185 3.61 27 13.36 2.90 7.33 3.23 0.37 51 1413.000 0.481 1.62 2218 270 3.36 28 14.71 3.20 7.01 3.31 0.44 45 1413.120 0.507 1.64 2478 283 3.62 29 12.04 3.40 7.57 3.16 0.35 38 12 7.6100.541 1.65 1284 60 2.66 30 14.70 14.00 6.98 3.41 0.49 83 18 11.990 0.5591.69 2287 170 3.86 31 12.47 1.20 6.41 3.44 0.38 32 11 8.560 0.582 1.82588 214 3.25 32 12.40 1.00 6.34 3.44 0.36 30 11 8.040 0.581 1.69 2542196 3.29 33 12.41 1.10 6.47 3.43 0.35 30 12 8.570 0.577 1.79 2547 2003.33

indicates data missing or illegible when filed

TABLE 4 Control wine in Wine in accordance accordance with with thepresent PARAMETERS the known art invention Variation % Alcohol (%) 13.1613.89 +5.55 Sugars (g/l) 1.5 1 −33 Titratable acidity (g/l 6.69 5.96−10.9 tartaric acid) pH 3.28 3.51 +7 Net volatile acidity 0.39 0.43+10.3 (g/l) Total SO₂ (mg/l) 74 24 −67.6 Free SO₂ (mg/l) 30 7 −76.7Intensity 18.71 26.69 +42.7 Malic acid (g/l) 0.60 0.1 −83.3 Totalpoliphenols 2740 3655 +33.4 (mg/l) Anthocyanins (mg/l) 455 780 +71.4Catechin e 3.42 3.95 +15.5 Epicatechin (mg/l)

1. A grape treatment and wine making process characterised by the stepsof: cleaning a first container by means of a fluid mixed with ozone;placing the grapes in said first container in closed vats and/orbuildings at controlled temperature; diffusing a fluid mixed with ozonewithin said vats and/or buildings at controlled temperature; cleaningsaid grapes placed in said first container by means of a fluid mixedwith ozone; cleaning a press by means of a fluid mixed with ozone;pressing said grapes with said press to produce must; cleaning a secondcontainer by means of a fluid mixed with ozone; placing said must insaid second container to produce fermented must; cleaning a thirdcontainer by means of a fluid mixed with ozone; placing said fermentedmust in said third container.
 2. A process as claimed in claim 1,characterised by comprising, prior to said pressing step, the steps ofbringing a stalk stripper into contact with a fluid mixed with ozone;stripping said grapes from their stalks.
 3. A process as claimed inclaim 1, characterised in that said fluid is water.
 4. A process asclaimed in claim 1, characterised in that said fluid is air.
 5. Aprocess as claimed in claim 1, characterised in that said firstcontainer comprises boxes, said grapes being placed in said boxes insingle or multi-layers.
 6. A process as claimed in claim 1,characterised in that said second container is a vessel or cask and/or asilo.
 7. A process as claimed in claim 1, characterised in that eachinstrument/equipment item used in said process is brought into contactwith a fluid mixed with ozone.
 8. A process as claimed in claim 1,characterised by not comprising the step of adding sulphites to saidmust.
 9. A process as claimed in claim 1, characterised in that saidthird container is a bottle.
 10. A process as claimed in claim 1,characterised in that said first, second and third container are cleanedwith water containing 6-8 mg of ozone per litre.
 11. Wine produced bythe process of claim 1, characterised in that said wine containspolyphenols and anthocyanins in a percentage greater than that of a wineproduced by a traditional process.